Thursday, December 31, 2009

It does get easier, honest

After designing 3 boards (well, actually one of those was a complete redesign after a failed attempt) with Eagle CAD, I have re-learned it's crazy interface.  The fourth board I did today in about 3 hours, from beginning the schematic capture to completing the board layout including passing DRC, and even the silk screen layer done.

I had time today to go back to the first board and add a feature, polish up the silk screen layer, and fix some minor DRC errors.  I think its important to get the DRC clean.  Otherwise, there is a tendency to pass over real problems the DRC is trying to tell you about, hidden in the "errors" that aren't really problems.  If the DRC is clean, then you at least know there are no problems that the computer can catch.  I hate finding a bug in a fabricated and assembled board only to discover that the problem was flagged in a DRC error that I overlooked back during the design capture stage.

Of course, this was the easiest of the boards so far.  Only 1x1 inch.  I got a little carried away and did the design without any signal routes on the bottom layer. There are four vias for routing power.

There are still two more boards to do.  One is even easier than this board.  It will be only one layer, roughly 3x6 inches.  I just have to figure out how to capture the design of a board that won't fit in the Eagle CAD free version's restriction of 4x3 inches.

The other board is the radio, which is the hardest board to design in this project.  But, my plan is to do the other boards and most of the software, then see if I have time to design a radio.  If not, then I won't have to worry about it, I'll just buy Atmel-based Zigbee modules.  If I do have time, then at least I should be competent at running Eagle CAD before tackling that job.

I've used up 13 of 30 days doing 3/5ths of the hardware design and I haven't started on the software.  While some of those were holidays that I didn't get anything done, some were very long days.  It's looking likely that I'll be buying those radios.

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